>>715989810World Chalice card storyline from Yugioh, popularized by being the beginner deck of the online game Master Duel.
That card in particular was the RPG "big brother" archetype.
>friend is the Chosen One>encounter a World Legacy item, the World Chalice>Chalice empowers you, him, your healer younger sister, and your pet dragon into proper four niggas in a row characters>Chalice is host to a holographic fairy who joins you>[plot]>fairy betrays your party at the adventure peak by hijacking your sister's body and transforming your allies into monsters>sister sacrifices herself to put an end to the madness>peace returns, but you want your sister back at any price>build an army of instrument-robots to conquer the world and assemble all of the World Legacy relics to resurrect her>also build a replica of your sister to keep you company>fairy was still inside the sister's original body>hijacks the merged relics to recreate the world>fortunately, you were such a great rival that your friend became a god to stop you>friend dives into her, learning that she was a scientist from the distant past whose baby died during the apocalypse (her wish was the same as your own)>merge with all of your machines and sister-replica to finish her off>friend accepts his newfound divinity to save the world from collapse, then departs for the stars>your sister is back, and you watch over her as a super robot>joined by your sister-replica as a fairy (true) sidekickNingirsu had a hard life.